Fatty acid amides are a class of lipid transmitters that include the endogenous cannabinoid anandamide (AEA) and the sleep-inducing chemical oleamide. The magnitude and duration of their signalling are controlled by enzymatic hydrolysis mediated by fatty-acid amide hydrolases 1 and 2 (FAAH, H2). Hydrolysis of AEA is described here (Wei et al. 2006). FAAH is localised to the ER membrane whereas FAAH2 is localised to lipid droplets (Kaczocha et al. 2010).